This application seeks partial support for the Federation of American Societies of Experimental Biology (FASEB) Summer Research Conference on "Polycystic Kidney Diseases: Molecular Pathways, Pathogenic Mechanisms and Translational Applications" to be held from August 6-11, 2005 in Saxtons River, VT. The planned conference follows a very successful, FASEB-sponsored inaugural conference that was held in August 2002. This meeting will highlight the exciting research progress in the interval three years, and thus provide a timely forum that integrates recent advances in basic research with applied themes. The conference will comprise a keynote address, nine regular scientific sessions, two 2-hour poster discussion sessions that will be organized based on the submitted abstracts (new, unpublished data), and a 2-hour session for late-breaking advances. The scientific program has been organized around three main themes. First, we will discuss the functional role of renal cystic disease proteins or cystoproteins in epithelial differentiation, polarity, and cell signaling, including their functional roles in signaling from the primary apical cilium. The second theme will take a broader view - examining cystoprotein function from a phylogenetic perspective; characterizing cystoprotein networks that are modulated by quantitative trait loci, and probing cystoprotein function in convergent pathways that have been implicated in phenotypically-diverse renal cystic diseases. The role of cystoproteins in non-renal epithelia and non-epithelial organs will also be explored. The final theme will have a translational focus - exploring biomarkers for disease progression and discussing targets for new and innovative therapies. The small size of the meeting (100-150 participants) with participants drawn from diverse disciplines ranging from nephrology and gasteroenterology, to cell biology and developmental biology, to molecular genetics and comparative genomics, to state-of-the-art imaging and pharmaceutical development, will provide an unparalleled opportunity for scientific cross-fertilization. By allowing ample time for scientific exchanges and critical discussion, the conference will serve as a conduit for exploring new experimental ideas and fostering new research collaborations.